Liquid chromatography, which is a method of separating materials in a sample by interaction between a mobile-phase (eluent) and a stationary-phase, has an advantage that various materials may be simultaneously separated by one-time injection of the sample.
Meanwhile, as a method for improving efficiency of analysis, there is a two-dimensional analysis method.
On-line multi-dimensional chromatography has been used to analyze a complicated sample. In some cases, this approach is referred to as column switching. According to a column switching method, a sample is divided into multiple fractions of treatable parts and additionally analyzed.
In the case of a two-dimensional approach, unwanted materials in a sample may be delivered into waste, and additional separation is performed by flowing an analyte, which is a target of interest, to a second column.
In the prior art document, various two-dimensional separation methods have been disclosed. For example, Steven R. Villasenor (Anal. Chem., 63, (1991), 1362-1366) disclosed a matrix removing technique using a heart-cut and column switching method for analyzing sulfite in an analgesic formulation.
As another technique associated with the two-dimensional separation method, an ultrahigh-pressure cation exchanger dual on-line solid-phase extraction/capillary reverse-phase liquid chromatography system capable of maximizing analysis efficiency of a complicated bio-sample and particularly minimizing a dead time by using a two-dimensional liquid chromatography system in which a strong cation exchange chromatography and a reverse-phase liquid chromatography are on-line connected to each other has been disclosed in Korean Patent Laid-Open Publication No. 2009-0058287 (Title: Ultrahigh-pressure cation exchanger dual on-line solid-phase extraction/capillary reverse-phase liquid chromatography system, Laid-Open Publication Date: Jun. 9, 2009).
As described above, a multi-dimensional chromatography technology has been developed up to now, but in view of removing a matrix effect, there is still limitation in selectively analyzing only a material of interest. Here, the matrix may be defined as follows. At the time of analyzing a specific material contained in an arbitrary sample all materials except for the material of interest may be collectively referred to as the matrix. At the time of analyzing the materials in the sample particularly using a liquid chromatography/mass spectrometry (LC/MS), in the case in which the matrix as described above has the same elution time as that of the material of interest, the matrix affects sensitivity of a mass spectrometer, such that it is difficult to obtain an accurate measurement result. This phenomenon is referred to as a matrix effect. Therefore, a technology for removing the matrix effect with relation thereto should be continuously developed.